Electrically controlled dashpot for carburetor throttles



May 26, 1953, v J. F. PURO 2,639,778

ELECTRICALLY CONTROLLED DASHPOT FOR CARBURETOR THROTTLES Filed Dec. 19, 1947 IN V EN TOR.

JbHu 1'. P020 BY AT TORNE Y Patented May 26, 1953 ELECTRICALLY CONTROLLED DASHPOT FOR CARBURETOR THROTTLES John F. Puro, Elmira, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application December 19, 1947, Serial No. 792,632

Claims. (01. 180-77) The present invention relates to carburetors for internal combustion engines and more particularly to a throttle control mechanism for said carburetors.

In the operation of automobiles equipped with a fluid coupling or transmission, the engine sometimes stalls if the throttle is moved quickly to closed position when the vehicle is not in motion since under this condition rapid and almost complete deceleration of the engine is produced by the braking effect of the coupling or transmission. To prevent stalling of the engine, a mechanism such as a dashpot is often used to delay or retard momentarily the complete closing of the throttle so that a relatively gradual deceleration of the engine to normal idling speed is obtained. While the delaying effect of the dashpot permits satisfactory deceleration and prevents stalling of the engine, it is undesirable in the operation of an overdrive mechanism since the delaying effect on the throttle tends to prolong the time required to synchronize the engine and vehicle speeds for engaging the overdrive. It is therefore one of the principal objects of the present invention to provide in a carburetor for an internal combustion engine a mechanism for delaying the closing of the throttle only during the time when the vehicle is at a standstill or is traveling at a relatively slow rate of speed.

Another object of the invention is to provide a mechanism for delaying the closing of the throttle when the vehicle is not in motion or is traveling at a relatively slow rate of speed and another mechanism for rendering the first mechanism ineffective when the vehicle is traveling in the cruising or high speed range.

A further object of the invention is to provide a simple, easily produced and readily assembled mechanism for controlling the operation of the throttle to give a momentary delay at the end of the closing movement of said throttle, but only only when he vehicle is at a standstill or is traveling at a speed less than that at which the overdrive cuts in.

Additional objects and advantages will appear from the following description and accompanying drawings, wherein one specific embodiment of the invention is disclosed.

In the drawings:

Figure 1 is a side view of a carburetor incorporating my invention, in which the fuel bowl and throttle regulating mechanism are shown in cross-section;

Figure 2 is an enlarged cross-sectional view of the throttle regulating mechanism; and

Figure 3 is a top plan view of the main body of the carburetor shown in Figure 1.

Referring more specifically to the drawings, numeral ll! designates an air horn of a single barrel downdraft carburetor, numeral I2 a fuel bowl mounted on and formed integrally with the main body, and I4 a throttle mounted in the carburetor induction passage l5 on a shaft I6 journalled in the throttle body I8, a flange 26 being provided at the base of said throttle body for securing the carburetor to an intake manifold (not shown). The throttle is adapted to be actuated by a throttle lever (not shown) mouned on one end of shaft l6. The fuel is delivered to the fuel bowl through conduit 24 andis controlled by a needle valve 26 and a float 28 mounted on a pivoted lever 30.

A dashpot, generally shown at 40, is provided to'prevent rapid closing of the throttle when the vehicle is not in motion or is in motion but traveling at a relatively slow speed and consists of a cylinder 42 disposed in the lower portion of the fuel bowl and a reciprocable piston 44 connected to the throttle shaft l6 by a rod 46 journaled in a sleeve 41 in the fuel bowl cover 48, a

rod 52 secured to the upper end of rod 46 and a lever 64 rotatably mounted on the end of the throttle shaft opposite the throttle lever. -A lever 56 for actuating the accelerating pump (not shown) is rigidly secured to said shaft adjacent lever 54 and is adapted to engage a lug 58 on one end of lever 54 during the closing movement of the throttle and rotate said lever in the direction to move piston 44 to the bottom of cylinder 42. A yieldable connection is also provided between'the two levers by a spring 60 so that, in the opening movement of the throttle, lever 54 is moved in the direction to lift said piston. The spring permits the throttle to be moved further after the upward limit of the piston stroke is reached. The position of stop screw 62, which is adapted to abut against a boss on the bottom side of the fuel bowl, determines the upward limit of the piston stroke.

The lower end of cylinder 42 is connected with the fuel 'bowl'by a conduit 64 in-which a-ball check valve 66 is provided to prevent the flow of fuel from cylinder 42 back through said conduit into the fuel bowl. The operation of the piston is regulated by the discharge of fuel through a passageway 68 extending through piston 44 and the lower end of rod 46 to the open end of cylinder 42, said passageway being so calibrated as to give the desired delaying action to the closing movement of the throttle.

The dashpot is rendered ineffective during certain engine or vehicle operating conditions by a solenoid 80 having a soft steel core 82 projecting into conduit 64 in the proximity of a steel ball 84 of the ball check valve. When the solenoid 80 is energized in response to variations in some operating conditions, such as speed, metallic core '82 becomes magnetized and attracts ball 84 to it, as shown in Figure 2, thus preventing said ball from seating over orifice 86. When the solenoid is de-energized, the magnet becomes demagnetized and releases ball 84, thus permitting the dashpot to function normally.

In the operation of the present throttle regulating mechanism used in conjunction with a fluid coupling or transmission and an overdrive, the solenoid 89 remains de-energized while the vehicle is at a standstill or in motion at relatively slow speeds so that ball 84 opens and closes orifice 86 as piston 44 is moved up and down by the opening and closing movement of the throttle. As the piston moves downwardly during the final stages of the closing movement of the throttle, fuel which was drawn into the cylinder through conduit 64 in bled back into the fuel bowl through passageway 58 which is calibrated to produce the desired delaying elfect in the closing movement of the throttle. As the speed of the vehicle approaches that at which the overdrive cuts in, the solenoid, which may be controlled by the governor for the overdrive, becomes energized and magnetizes core 82 which holds ball 84 away from orifice at and permits fuel to return freely to the fuel bowl from cylinder 42. When the speed of the vehicle decreases to that at which the overdrive cuts out, the solenoid becomes de-energized and the core demagnetized, releasing ball 84, which then prevents the return of fuel through conduit 64 to the fuel bowl. Thus, the dashpot again becomes effective in delaying the final closing movement of the throttle.

Another mechanism for performing the same function is disclosed and claimed in copending application Serial No. 41,115 filed July 28, 1948, in the name of Richard R. Strebinger and since issued as Patent Number 2,598,855.

It is contemplated that other arrangements of elements than that shown in the accompanying drawings may be provided without departing from the scope of the present invention. For example, the calibrated passageway 68 may be replaced by a conduit by-passing valve 66 or by a slot in the edge of orifice 86. Further, a diaphragm forming a movable wall for a chamber such as the low end of cylinder 42 may be used in place of piston 44. In certain carburetor constructions, core 82 may be so disposed in relation to conduit 6t and orifice 86 that, when said core is magnetized, ball 86 will be removed from the path of the fluid, so that there will be no tendency for the fluid to displace the ball from the magnet until the latter is demagnetized. Additional modifications of the present throttle regulating mechanism as well as other uses therefor will occur to those skilled in the art.

I claim:

1. In a carburetor for an internal combustion engine, an induction passage with a throttle therein; a throttle actuating means; a source of fluid; a chamber; a movable wall for said chamber; a conduit connecting said chamber with said source of fluid; a valve in said conduit adapted to be moved toward closed position by fluid flowing from said chamber; a calibrated passageway connecting said chamber with the source of fluid; a linkage connecting said movable wall with the throttle actuating means for moving said wall in the direction to draw fluid into said chamber during the opening movement of the throttle and for moving said wall in the direction to discharge fluid from said chamber near the end of the closing movement of the throttle, the capacity of said conduit being such as to permit said chamber to fill readily with fluid and the capacity of said passageway alone being such as to prevent said chamber from being readily emptied, whereby the closing movement of the throttle is retarded; a magnetizable member extending into said conduit adjacent said valve;

and means spaced from said conduit for magnetizing said member under certain engine or vehicle operating conditions to open said valve.

2. In a carburetor for an internal combustion engine, an induction passage with a throttle therein; a throttle actuating means; a fuel bowl; a chamber; a movable wall for said chamber; a conduit connecting said chamber with the fuel bowl for readily admitting fuel into said chamher; a valve element in said conduit adapted to be moved toward closed position by fluid flowing from vsaid chamber; a calibrated passageway connecting said chamber with the fuel bowl for permitting the fuel to pass slowly from said chamher; a linkage connecting said movable wall with the throttle actuating means for moving said wall in the direction to draw fuel into said chamber as the throttle is opened and for moving said wall in the direction to discharge fuel from said chamber as the throttle is closed; a magnetizable bar projecting into said conduit adjacent said valve element; and means spaced from said conduit for magnetizing said bar under certain englue or vehicle operating conditions to open said valve.

3. In a carburetor for an internal combustion engine, an induction passage with a throttle therein; a throttle actuating means; a fuel bowl; a chamber; a movable wall for said chamber; a conduit connecting said chamber with the fuel bowl for readily admitting fuel into said chamber; a check valve including an orifice with a ball adapted to seat over said orifice for preventing fuel from flowing to the fuel bowl through said conduit; a calibrated passageway connecting said chamber with the fuel bowl for permitting the fluid to pass slowly from said chamber; a linkage connecting said movable wall with the throttle actuating means for moving said wall in the direction to draw fuel into said chamber during the opening movement of the throttle and for moving said wall in the direction to discharge fuel from said chamber near the end of the closing movement of said throttle valve; a magnetizable member extending into said conduit between said ball and chamber; and means spaced from said conduit for magnetizing said member under certain engine or vehicle operating conditions to hold said ball from said orifice.

4. In a carburetor for an internal combustion engine, an induction passage with a throttle therein; a throttle actuating means; a fuel bowl; a chamber; a movable wall for said chamber; a conduit connecting said chamber with the fuel bowl for readily admitting fuel into said chamher; a check valve including an orifice and a ball adapted to seat over said orifice for restricting the flow of fuel to the fuel bowl through said conduit; a linkage connecting said movable wall with the throttle actuating means for moving said wall in the direction to draw fuel into said chamber during the opening movement of the throttle and for moving said wall in the direction to discharge fuel from said chamber near the end of the closing movement of the throttle; a magnetizable bar projecting into said conduit between said ball and chamber; and electrical means spaced from said conduit for magnetizing said bar under certain engine or vehicle operating conditions to hold said ball from said orifice.

5. In a carburetor having a throttle and a fuel bowl: 2, dashpot for regulating the closing movement of said throttle comprising a cylinder; a piston; a linkage for connecting said piston with said throttle; a restricted calibrated passage connecting said cylinder with said fuel bowl; a second passage connecting said cylinder with said fuel bowl; a, restriction in said second passage; a ball in said second passage between said cylinder and said restriction; a, magnetizable bar projecting into said second passage between said ball and chamber; and electrical means spaced from said conduit for magnetizing said bar under certain engine or vehicle operating conditions to hold said ball from said restriction.

JOHN F. PURO.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,960,432 Barker et a1. May 29, 1934 2,082,710 Mallory June 1, 1937 2,296,646 Matulaitis Sept. 22, 1942 

